This invention relates generally to metal ion lasers. An evaporation metal source and associated expensive and unreliable high temperature ovens used in some of these prior art electron beam pumped metal ion lasers have inhibited the commercial development of metal ion lasers employing high temperature ovens. For example, copper, silver, and gold require oven temperatures greater than 1000 degrees centigrade to obtain sufficient metal density for laser operation.
Metal ion lasers known in the prior art provide discrete output wavelengths in the 220-2000 nanometer spectral region on a continuous basis as described by D. Gerstenberger, R. Solanki, and G. Collins, Hollow Cathode Metal Ion Lasers, QE-16, No. 8 IEEE JOURNAL OF QUANTUM ELECTRONICS 820 (August, 1980). Prior designs of metal ion lasers generally fall into three categories. First, the ions from a rare gas discharge created in a capillary tube act together with metal vapor thermally generated by an external oven, or discharge heating to create laser action from metal ions. Secondly the ions created in a hollow cathode discharge react together with the metal vapor created by cathode sputtering in the same hollow cathode discharge to create laser action from metal ions. Thirdly, electron beam pumped metal ion lasers employing external ovens to create the required metal density have been demonstrated and reported by J. Rocca, J. Meyer, and G. Collins, 1-W cw Zn ion laser, 43(1) APPL. PHYS. LETT. 37 (July 1, 1983).
Some disadvantages of these prior art metal ion lasers are as follows. The relatively low density of energetic electrons in the hollow cathode discharge and the low cathode lifetime (100 hours) in a hollow cathode discharge sputtering environment have been barriers to the practical development of prior art metal vapor ion lasers employing hollow cathodes. An evaporation metal source and associated expensive and unreliable high temperature ovens used in some of these prior art electron beam pumped metal ion lasers have inhibited the commercial development of metal ion lasers employing high temperature ovens. For example, copper, silver, and gold require oven temperatures greater than 1000 degrees centigrade to obtain sufficient metal density for laser operation.